Microsoft last week stopped offering Windows 10's November upgrade as a disk image, shutting down the route many had used to skip the wait as the company slowly rolls out the refresh via Windows Update.

The .iso files are still available, but when downloaded using Microsoft's Media Creation Tool, they now install the original July 29 edition of Windows 10, not the November upgrade as they did earlier.

Windows 10 users impatient with the slow, staggered process Microsoft uses to upgrade devices through Windows Update had turned to the disk images and the Media Creation Tool to avoid the wait. Microsoft had, in fact, pointed users to the latter as a way to jump the queue.

Gabriel Aul, engineering general manager for Microsoft's OS group, suggested the Media Creation Tool and the disk images in a tweet on Nov. 12, the day the company released the refresh.

Microsoft has dubbed the upgrade -- the first for Windows 10 -- as 1511 to mark the month and year in the yymm format it's increasingly applied to software that will be regularly refreshed under a service-style model.

Reports of the change first appeared yesterday on Microsoft's support discussion forum. "I cannot find the Windows 10 November Update ISO on Microsoft's download website," said Berk Babadogan on one thread. "Only RTM ISO (Build 10240) available. A week ago, I [could] download November Update ISO from here. However, it suddenly disappeared this week, so I cannot download now."

Others, including Greg Carmack, a Microsoft MVP (Most Valuable Professional), confirmed that Microsoft had withdrawn 1511 when using the Media Creation Tool. "I inquired via MVP Communications Channel and just learned that the Fall Update v.1511 has apparently been taken down and replaced with original Release Version," said Carmack, referring to the July 29 edition.

Computerworld confirmed on Sunday that Media Creation Tool downloads point to the July 29 version, tagged as build 10240. A download of the tool on Nov. 13, a day after the November upgrade's release, had instead referenced build 10586, a label assigned to 1511.

Microsoft acknowledged the the disappearance of the November upgrade, but did not provide clues about why it had been yanked. Instead, a spokesman simply repeated the line from the Media Creation Tool's website about it not being able to upgrade Windows 10 to 1511, and implied that if the company had, in fact, removed the upgrade from Windows Update, it would restore it at some point. "The November update will be available via Windows Update," the spokesman said in an email response to questions. "If you don't see the November update yet, you will see it soon as it is rolling out in a phased approach."

By yanking the November upgrade, Microsoft has limited how users -- whether those running Windows 10, or the earlier Windows 7 and Windows 8.1 editions eligible for a free upgrade -- obtain the latest version of Windows 10.

Those upgrading from Windows 7 or Windows 8.1 must now go through two upgrades: First to July 29's build 10240, and then again to 1511, or build 10586. Each is at least a 3GB download.

Customers already running Windows 10's build 10240 must hang tight and wait for Microsoft to offer the November upgrade in Windows Update, then download that for each device. That means Windows 10 users will no longer be able to create bootable, installable media -- typically a USB thumb drive, but alternately a DVD disc -- to upgrade multiple machines to 1511 without having to download the massive file to each system, consuming bandwidth and taking time.

Previously, Microsoft had been clear that it would use Windows Update to refresh Windows 10 with the two-to-three-times-a-year upgrades, as well as the monthly security updates. But it had also pledged that it would offer disk images in .iso file format for each upgrade to give advanced users another way to keep their devices up to date.

The Windows 10 Media Creation Tool now downloads the July 29 version -- identified here as build 10240 -- rather than the newer November upgrade because Microsoft has stopped users from upgrading via a disk image in .iso file format.